Justin Timberlake surprised some young fans yesterday when he visited the children's ward of Manhattan's Mount Sinai hospital. The SexyBack singer taped a show at Central Park for Ellen Degeneres and ducked across the street afterwards to stun patients with a two-hour walkabout at the hospital. "It was a surprise visit, and the kids were, like, screaming," said JT's rep. "He went all over the hospital, floor to floor. He does this kind of thing all the time."